Computers arc known to include a central processing unit ("CPU"), video graphics processing circuitry, cache memory, floppy disk memory, hard drive memory, and peripheral input/output ports, which allow peripheral devices such as a CRT display (or monitor), printer, etc. to be coupled to the computer. In addition, some computers may include a television encoder, such that the computer can receive and display television signals. Such television signals include broadcast television, cable television, satellite television VCR (videocassette recorder) transmissions, and/or DVD video transmissions.
FIG. 1 illustrates a portion of such a computer system 10 that includes a graphic controller 12 and a TV encoder 14. The graphics controller 12 controls the processing of video information that is to be presented on the computer monitor 28, while the TV encoder 14 generates video outputs such as composite video 30, S video Y 32, and S video C 34 for display on a television. The graphics controller 12 includes video circuitry 16 and a digital to analog converter (DAC) 18. The video circuitry 16 receives video inputs 26 that are in the Y,Cb,Cr format and converts the input 26 into RGB (Red, Green, Blue) data, which may be 16 or 24 bits in length. The video circuit 16 may also scale the video inputs 26 prior to converting them to RGB data. The DAC 18 converts the digital 8 bit RGB data into analog signals such that they may be displayed on the monitor 28.
The TV encoder, upon receiving the eight bit RGB data, converts the data into YUV data via an RGB to YUV converter 20. The converted data is then scaled by a scaling circuit 22 and converted to an analog signal by the digital to analog converter 24. In such a system, the video input 26 is converted to a RGB graphics data format and then reconverted to a YUV video format. Such conversions reduce the video quality of video signals being presented at the video outputs 30, 32 and 34. In addition to the redundant format conversions, the circuit of FIG. 1 requires two circuits to process video data and graphics data. In laptop computer applications, the multiple circuit approach of FIG. 1 requires additional real estate, which adds to the overall size of the laptop computer.
Therefore, a need exists for a method and apparatus that integrates video data processing and graphics data processing without redundant format conversions.